• 한국작물학회지
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• 제12권
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• pp.25-29
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• 1972

1. 광조건에 의한 흡수량 차이는 $P_2$ $O^52$, Ca의 순서로 줄었다. 즉 암조건에서의 $P_2$ $O^52$흡수는 광조건에 비해 약 1/6정도이였으나 Ca에서는 1/2정도였다. 2. 상대습도는 Ca의 흡수를 약간 변화시켰으나 $P_2$ $O^52$나 Mn은 습도에 별 영향을 받지 않고 흡수되었다. 3. 규소함량이 다른 수도체간의 각각 동위원소흡수는 일률적으로 규소무처리구에서 제일 많았고 다음이 70.140ppm으로 생육시킨 수도가 제일 적게 흡수했다. 이는 곧 수도체내의 규소함량과 양분흡수와 긴밀한 관계가 있음을 뜻한다. 4. 뿌리에서부터 줄기로의 이행률을 보면 Ca이 1보다 컸고 Mn이 평균 0.5(1/2) $P_2$ $O^52$이 0.2(1/5) 정도였다. 이것은 이들 영향요소들의 수도체 흡수의 특이한 pattern이라고 생각된다.

• Journal of Korean Dental Science
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• 제4권2호
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• pp.73-78
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• 2011

Purpose: $HCO_3{^-}$ is the most important ion to buffer the acidity of saliva. The transport of $HCO_3{^-}$ is mediated by electrogenic $Na^+/HCO_3{^-}$ cotransporter 1 (NBCe1), which expressed in various tissues including salivary glands, kidney and pancreas, etc. This experiment was performed to investigate regulatory site of NBCe1involved in the pH regulation using various mutants of NBCe1. Materials and Methods: Human parotid gland NBCe1 (hpNBCe1) and mutants by deletion of 1~285 bp and 1~1,035 bp were prepared. After microinjection of each cRNA to oocytes of Xenopus laevis, they were incubated for 2~3 days. The function of each protein was tested by electrophysiological method. Results: When oocytes were exposed to the $HCO_3{^-}$ buffered solution, 1~285 bp deleted mutant hpNBCe1 evoked a marked hyperpolarization ranging from -90 mV to -160 mV (average: -134 mV; n=12) compared to the full length of hpNBCe1. Although 1~1,035 bp deleted mutant hpNBCe1 was also expressed in the plasma membrane, but it did not show any changes of membrane potentials. Conclusion: Our deletion mutant study demonstrated that 1~285 bp of the NBCe1 is the major domain to determine $HCO_3{^-}$ transport ratio.

• The Korean Journal of Physiology
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• 제7권2호
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• pp.39-47
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• 1973

The influences of the acute hemorrhage on the intestinal functions were studied in the rabbits subjected to acute bleeding, amounting 1.5-2% of the body weight. The motility and the absorptive capacity of the ileum were compared before and after the bleeding. Transfusion of shed blood was also performed in order to see whether the deteriorations were reversible or not. The tension developed in the direction of the longitudinal axis of the ileum was recorded through an appropriate transducer, and the frequency of the rhythmic contraction was counted throughout the procedure. Test solution, 10ml in amount, was placed in the loop of the ileum, and the samples were drawn at zero time and at 20 minutes. Triplicated procedures were repeated on the same loop;namely, before and after bleeding and after transfusion. The test solution was composed of 200 mg% urea, 218 mEq/l of NaCl and 150 mg% of polyethylene glycol (PEG) No. 4,000 in distilled water. The latter substance was used as a marker substance for the volume change of the loop. The results obtained were as follows; 1. The motility of the ileum suffered little effects by acute hemorrhage. However, minor fluctuations were seen in the frequency of the rhythm, showing a slight tendency of decreasing rhythmicity, and it was reversed by transfusion. 2. Diminution of absorptive capacity of urea was noticed in acute hemorrhage and it was interpreted as the consequence of the secondary effect of the retardation of the active transport mechanism governing the sodium transport 3. Absorption rate of the sodium ion was dropped in the hemorrhage, suggesting the indispensable need of the blood supply. 4. Osmolarity of the luminal fluid remained higher in the case of acute hemorrhage. 5. There was a tendency of retaining more fluid in the intestinal lumen in acute hemorrhage, comparing with that observed prior to the bleeding. 6. The deteriorations in the absorptive capacity were restored by transfusion of shed blood.

• Journal of Photoscience
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• 제9권3호
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• pp.45-48
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• 2002

Microbial rhodopsins, photoactive 7-transmembrane helix proteins that use retinal as their chromophore, were observed initially in the Archaea and appeared to be restricted to extreme halophilic environments. Our understanding of the abundance and diversity of this family has been radically transformed by findings over the past three years. Genome sequencing of cultivated microbes as well as environmental genomics have unexpectedly revealed archaeal rhodopsin homologs in the other two domains of life as well, namely Bacteria and Eucarya. Organisms containing these homologs inhabit such diverse environments as salt flats, soil, freshwater, and surface and deep ocean waters, and they comprise a broad phylogenetic range of microbial life, including haloarchaea, proteobacteria, cyanobacteria, fungi, and algae. Analysis of the new microbial rhodopsins and their expression and structural and functional characterization reveal that they fulfill both ion transport and sensory functions in various organisms, and use a variety of signaling mechanisms. We have obtained the first crystallographic structure for a photosensory member of this family, the phototaxis receptor sensory rhodopsin II (SRII, also known as phoborhodopsin) that mediates blue-light avoidance by the haloarchaeon Natronobacterium pharaonis. The structure obtained from x-ray diffraction of 3D crystals prepared in a cubic lipid phase reveals key features responsible for its spectral tuning and its sensory function. The mechanism of SRII signaling fits a unified model for transport and signaling in this widespread family of phototransducers.

• 대한금속재료학회지
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• 제49권10호
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• pp.818-822
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• 2011

ZnO nanorods were grown on Au-coated Si substrates by vapor phase transport (VPT) at the growth temperature of $600^{\circ}C$ using a mixture of zinc oxide and graphite powders as source material. Au thin films with the thickness of 5 nm were deposited by ion sputtering. Temperature-dependent photoluminescence (PL) was carried out to investigate the optical properties of the ZnO nanorods. Five peaks at 3.363, 3.327, 3.296, 3.228, and 3.143 eV, corresponding to the free exciton (FX), neutral donor bound exciton ($D^{\circ}X$), first order longitudinal optical phonon replica of free exciton (FX-1LO), FX-2LO, and FX-3LO emissions, were obtained at low-temperature (10 K). The intensity of these peaks decreased and their position was red shifted with the increase in the temperature. The FX emission peak energy of the ZnO nanorods exhibited an anomalous behavior (red-blue-red shift) with the increase in temperature. This is also known as an "S-shaped" emission shift. The thermal activation energy for the exciton with increasing temperature in the ZnO nanorods is found to be about 26.6 meV; the values of Varshni's empirical equation fitting parameters are = $5{\times}10^{-4}eV/K$, ${\beta}=350K$, and $E_g(0)=3.364eV$.

• Carbon letters
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• 제17권1호
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• pp.39-44
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• 2016

The work presented in this report was a detailed comparative study of the electrochemical response exhibited by graphite anodes in Li-ion batteries having different physical features. A comprehensive morphological and physical characterization was carried out for these graphite samples via X-ray diffraction and scanning electron microscopy. Later, the electrochemical performance was analyzed using galvanostatic charge/discharge testing and the galvanostatic intermittent titration technique for these graphite samples as negative electrode materials in battery operation. The results demonstrated that a material having a higher crystalline order exhibits enhanced electrochemical properties when evaluated in terms of rate-capability performance. All these materials were investigated at high C-rates ranging from 0.1C up to 10C. Such improved response was attributed to the crystalline morphology providing short layers, which facilitate rapid Li⁺ ions diffusivity and electron transport during the course of battery operation. The values obtained for the electrical conductivity of these graphite anodes support this possible explanation.

• Korean Chemical Engineering Research
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• 제47권4호
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• pp.476-480
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• 2009

본 연구는 리튬 이차전지용 고분자 전해질 복합재료에 관한 것으로, 고분자는 poly(ethylene oxide)(PEO)와 poly(methyl methacrylate) (PMMA) 블렌드를 사용하고, 용매로는 Ethylene carbonate(EC), 그리고 $LiClO_4$를 리튬염으로 하는 전해질 복합체 필름을 제조하였으며, PMMA의 함유량에 따른 고분자 전해질의 전기화학적 특성을 관찰하였다. 제조된 고분자 전해질의 결정화도와 이온전도도는 시차주사열량계(DSC)와 주파수반응분석기(FRA)로 분석하였다. 그 결과 PMMA의 함량을 증가시킴에 따라서, PEO의 결정 영역이 감소하고 이온전도도가 증가하였다. 또한, PMMA의 함량이 20 wt.% 이상인 경우, 고분자 블렌드필름에서 상분리되는 현상을 관찰하였다. 즉, SEM 분석결과에 의해서, PMMA 주성분 영역과 PEO 주성분 영역의 구분이 가능하였다. 고분자 전해질의 이온전도도는 20 wt.% 첨가한 경우 가장 큰 이온전도도를 가지며, 함유량이 20 wt.% 이상에서는 PMMA 상의 증가로 인해 다소 감소된 이온전도도 변화를 나타내었다.

• Asian Journal of Atmospheric Environment
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• 제12권1호
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• pp.67-77
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• 2018

To investigate the effects of forest and the surrounding natural and anthropogenic sources on the bulk depositions on forested land, this study examined differences in ion concentrations between wet-only and bulk samples at two forested sites in Japan. The surrounding natural and anthropogenic sources at each site were different; Shirasaka is in a rural area and Tanashi is an urban environment. The volume weighted (vw) mean concentrations of $K^+$ and $Ca^{2+}$ in the bulk samples were significantly (p<0.05) higher than those in the wet-only samples at both sites. The forest canopy and a nearby incineration plant were hypothesized to be the main sources of $K^+$ contaminants at Shirasaka and Tanashi, respectively. The transport of sea salt and urban dust may explain the presence of enriched $Ca^{2+}$ concentrations in the bulk samples at Shirasaka and Tanashi, respectively. The $NH_4{^+}$ concentrations in the Shirasaka bulk samples were significantly (p<0.05) lower than those in the wet-only samples. The vw mean $SO{_4}^{2-}$ and $NO_3{^-}$ concentrations in both sample types were not significantly different at either site. This study demonstrated that the ion concentration differences between wet-only and bulk samples were affected by nearby natural and anthropogenic sources even at forest sites, similar to previous findings for non-forested locations. However, the $K^+$ concentration differences between wet-only and bulk samples may be higher owing to forest sources, even in the absence of anthropogenic sources.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.484.2-484.2
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• 2014

There are many efforts to improving the power conversion efficiencies (PCEs) of dye-sensitized solar cells (DSCs). Although DSCs have a low production cost, their low PCE and low thermal stability have limited commercial applications. This study describes the preparation of a novel multifunctional polymer gel electrolyte in which a cross-linking polymerization reaction is used to encapsulate $TiO_2$ nanoparticles toward improving the power conversion efficiency and long-term stability of a quasi-solid state DSC. A series of liquid junction dye-sensitized solar cells (DSCs) was fabricated based on polymer membrane encapsulated dye-sensitized $TiO_2$ nanoparticles, prepared using a surface-induced cross-linking polymerization reaction, to investigate the dependence of the solar cell performance on the encapsulating membrane layer thickness. The ion conductivity decreased as the membrane thickness increased; however, the long term-stability of the devices improved with increasing membrane thickness. Nanoparticles encapsulated in a thick membrane (ca. 37 nm), obtained using a 90 min polymerization time, exhibited excellent pore filling among $TiO_2$ particles. This nanoparticle layer was used to fabricate a thin-layered, quasi-solid state DSC. The thick membrane prevented short-circuit paths from forming between the counter and the $TiO_2$ electrode, thereby reducing the minimum necessary electrode separation distance. The quasi-solid state DSC yielded a high power conversion efficiency (7.6/8.1%) and excellent stability during heating at $65^{\circ}C$ over 30 days. These performance characteristics were superior to those obtained from a conventional DSC (7.5/3.5%) prepared using a $TiO_2$ active layer with the same thickness. The reduced electrode separation distance shortened the charge transport pathways, which compensated for the reduced ion conductivity in the polymer gel electrolyte. Excellent pore filling on the $TiO_2$ particles minimized the exposure of the dye to the liquid and reduced dye detachment.

• 한국대기환경학회지
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• 제27권6호
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• pp.723-733
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• 2011

The ionic compositions were analyzed from the TSP samples collected at Gosan site in Jeju Island between 2000 and 2008, in order to examine the characteristics of atmospheric aerosols in accordance with the meteorological conditions. For the Asian Dust influence on the ionic compositions, the concentration ratios of $NH_4{^+}$, nss-${SO_4}^{2-}$, $NO_3{^-}$, and $K^+$ were about 1.2~2.3 during Asian Dust over Non-Asian Dust periods, noticeably that of nss-$Ca^{2+}$ was 6.8. Meanwhile the concentrations of nss-${SO_4}^{2-}$, $NO_3{^-}$, and $NH_4{^+}$ have increased as 1.8~4.4 times during the haze event periods, and 1.0~1.6 times during the fog and mist events. The ion balance has resulted that the anionic concentrations are relatively lower than the cationic concentrations, and the discrepancy appears more decidedly as a strong Asian Dust effect. The ammonium ion balance has shown that it exists as a mixture of $NH_4HSO_4$ and $(NH_4)_2SO_4$. The concentration ratios of nss-${SO_4}^{2-}/NO_3{^-}$ for Asian Dust, haze, fog-mist, and non-event periods were respectively 1.8, 5.9, 4.6, and 2.9, which were higher values compared to those in urban areas of China as well as other domestic regions. Especially, the high ratios of sulfur oxides could be presumed by the fact that the longrange transport of air pollutants from Asia continent might affect the atmospheric aerosols of Jeju Island.